The Dawn of Life in a $5 Toaster Oven
How a homemade piece of lab equipment is recreating chemical evolution on early Earth.
BY JOHNNY BONTEMPS
ILLUSTRATION BY JACKIE FERRENTINO
AUGUST 27, 2015
God might just as well have begun with a toaster oven. A few years ago at a yard sale, Nicholas Hud spotted a good candidate: A vintage General Electric model, chrome-plated with wood-grain panels, nestled in an old yellowed box, practically unused. The perfect appliance for cooking up the chemical precursors of life, he thought. He bought it for $5.
At home in his basement, with the help of his college-age son, he cut a rectangular hole in the oven’s backside, through which an automated sliding table (recycled from an old document scanner) could move a tray of experiments in and out. He then attached a syringe pump to some inkjet printer parts, and rigged the system to periodically drip water onto the tray.
Today the contraption sits atop a workbench in Hud’s laboratory at the Georgia Institute of Technology, where he directs the Center for Chemical Evolution, a multi-university consortium funded by NASA and the National Science Foundation. For the past two decades, he has been hunting for the chemical recipes that could explain how life arose on Earth. When scientists began investigating life’s molecular origin in the 1950s, they assumed that the first biological molecules formed spontaneously from a soup of primordial compounds: a lucky marriage of the right ingredients, under the right conditions, at the right time. Hud and his colleagues are now finding that the spark of life may have struck much more gradually, not by chance but via a long chemical evolution.
The toaster is his latest proving ground. It simulates the cycles of cool and hot, and wet and dry, that Hud suspects jump-started this evolutionary process, millions of years before the first cellular life forms emerged. It mimics dew condensing at night and evaporating with the sunrise; rain puddles filling up and drying out; coastal lagoons flooding and emptying with the tides. Hud calls it the “day-night machine.”
On a spring day last year, he and I are huddled around the homebuilt device, watching it work. Outside of the oven, the syringe delivers a few droplets of water into each of six wells in a ceramic plate on the sliding tray. For the purpose of this demo, the wells are empty; during experiments, they contain a mixture of simple molecules, or monomers, like those believed to have been present on early Earth. The tray disappears into the oven, sealing it shut. As the temperature rises to 185 degrees Fahrenheit (85 degrees Celsius), the water evaporates—the first day. A few minutes pass, and the tray slides out. The wells cool, water drips, and in goes the tray—the second day.
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Read more here/Leia mais aqui: The Nautilus
